Do you need to change spark plugs after carbon tracking?

Joined
Dec 10, 2018
Messages
230
Location
New York City
A few weeks ago, I noticed my engine would "stumble" in drive when waiting at a stop light. It would do this a few times, but no check engine light came on.

Eventually, I connected my scan tool and found out cylinder 5 had 20 misfires.

I changed all sparkplugs 20K miles ago with OEM Double Platinum ones. So I figured an ignition coil is probably on its way out. My car has 120K miles on it. I bought a used coil in case I misdiagnosed it.

When I got the part, I began to replace it. When I removed the original ignition coil, I saw what appeared to be carbon tracking inside the boot. It was a thin white line along the inside of the boot.

Now in this case I would have changed the spark plug, But I didn't have a new plug or spark plug socket with me. So instead, I put a liberal amount of di-electric grease inside the new ignition coil boot, and put the new coil in.

It's been a few hundred miles and I don't have the stumble anymore.

Should I go back and change the spark plug? It's a PITA to access it. I know if the carbon residue is still on the plug, it could eventually start tracking again. But maybe with enough Di Electric grease, that won't happen. I did buy the new spark plug just in case.
 
Joined
Mar 20, 2008
Messages
12,521
Location
USA
If it doesn't do anything, don't worry about it. If you do change the spark plkugs, use iridium, since it's difficult in your car.
 
Joined
Dec 28, 2014
Messages
1,602
I mean, it’s not doing anything now, so I suppose just let it go till it happens again.
 
Joined
Oct 3, 2010
Messages
2,033
Location
RI
If it starts skipping again change the plug. Carbon tracking along the porcelain is a micro hole from arcing
 
Joined
Oct 20, 2020
Messages
21
Spark plugs are so inexpensive. Just change them out. May not change anything, but surely won't hurt.
 
Joined
Dec 8, 2011
Messages
686
Location
MO, USA
You can worry about what-ifs all day long. What about the unburnt gas hitting the converter. oops. Follow the advice here or not
 
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